Pusher



S. B. MARTIN Nov, 28, 1944.

PUSHER Filed Oct. 10, 1942 3 Sheets-Sheet l INVENTOR. STODDA PD B.MART/N BY V I A TTOE/VE-YS Nov. 28, 1944. a a A T N 2,363,890

PUSHER Filed Oct. 10, 1942 3 Sheets-Sheet 2 VENTOR. E- MART/N BY ywwwNov. 28, 1944. s. B. MARTIN 2,363,890

PUSHER Filed Oct. 10, 19 42 3 Sheets-Sheet 5 fig-14 2/2 340 324 3/7 2/6INVENT OR. 570E174 ED .5. NAP/7A! BY MYWM A 7' TOE/VEYS Patented Nov.28, 1944- .v UNITED STATES; PATENT Y Q FFICE 7 2,363,890. I- p I PUSHER'stoaaara na Martin, ome Application October 10,1942,'."s'e;a1;1sro.41,559'

18 Claims.

' Thisinvention nelaiteseto improyementsinostock feed fingers orpushers: oi the: e employed automatic screw"- machines Each spindle-ofanautomatic screw'maohine ordinarily surrounds a rotating: co-llet tubehaving aacollet at its: forward end which is arranged to be' compressedradially to grip-andiirotate a: bar

of: stock: fed: axially through the tube At the endioi each cycle: ofoperation the projecting: end

of stock is cutoff from the: hanwhereupon the coilet opens and a newlength of: stock is ied forwardly and the colletis again closed to grip.the stoek'andrepeat the cycle of operation. The stock is ordinarily fedforward by a pusher: car'- by a reciprocating pusher tube arrangedbetween and coaxial with the collet tube and the bam'ofistocln iIn-z'the conventional machine the pusher: is simply a spring bushingexerting a constant grip om the bar of stock is moved forwardly aft'e'nthe collet opens until the forward end of the-when strikes alsto'c'kgauge; The c'ollet then grips the: bar and the pusher is retracted. one

surfaces of the pusher are rapidly" worn out by the friction: of thereturn strokes;

The principal objectsof this invention are to- OQlilBiHE'flih aipusher'a one-way gripping mechanisnr, removable pads for gripping various sizesof stock up to and including theinaximum capacity; of the machine; andmeans for releasing the gripping action when it is desired to withdrawthestoclsf to dispose the one-way gripping mechanism' and all necessaryabutment's' between the shell andpads' within thetth'iekne'ss of thewall ofth'e' shell; to eliminate all loose or readily separable parts.except the removable pads or bushingC; and'to simplify andred'uce theoost of pusher'sl of this type. Other objects. and advantages,

Willi appear in the following detailed description 4 ofpreferred'embodiments of this invention.

The present invention is an improvement on the subject-matter disclosedin my co -pending application, Serial No. 446,754, filed June 12, 1942.

In the accompanying drawings:

Fig. 1a is: aside elevation-of a complete: pusher embodying the presentinventiom i Fig; 2' isalongitudinal sectionL oi the improved pus-hen,view being takenton a plane indicatedby'linei'L-lofvFig;1;; v I I Fig. 3is a crqsssectiontof the shell and bushingwaken on aplane indicated bythe 3 -3 ofFigc. 2 p Fig-A is anelevarional view otthe bushing with apontioni shown inseotion the interest of clari- Fig-, 5: is an sideelevation of: a slightly modified formaof pusher; v 4 k Fig. 6 is a,different elevation of the pushershown in Fig.5, partly sectioned onthel ine 6 3 Fig-.- 7 is a section taken on the plane indicated theline- M of Fig.- 5, but; with the bushing turned: from: its-position inFigsti;

:8ris asection on the line 8-&' of: Fig.- 5;

Fig'. 94s a section corresponding to Figs. 7 and 8;but with: the:bushing turned: slightly from the position shovmimFig; 8-;

Fig. 10 is a longitudinal seoti'on through the bushing shown in Figs. 5to 9;

. Fig; l-l= is? an' end: View of the front oi the pushershown" inwFig.5' with thestock removed;

Fig. 1.2- is -ain elevation of a+ fiurther modified form of the pusher;v v

Fig-. 1-3 is acrosssection taken on the line l 3i -l 3-of Fig. 13 p'Fig: 14

a longitudinah sectiontaken on the line li -14 M" Fig, 13;,

Fig. 15 is an elevation, partly sectioned; of am other modified form ofthe pusher;

g-z 16 is aisection taken on. the line Iii-t5 of Fig-215p Fig is" alongitudinal-c section through the bushing showniimFigs.-1-5-ancb.16-;

Fig. 18- isia; longitudinal section through theshellzshown in Fig s.-l-5 and 16 writhithe: bushing removed; and I 1*9 isia developed: view ofthe inner surface: of. the shell shown in Figs. 15 and 16;

Riefienring to= thedrawings the; pusher of the present invention.embodies: generally as push'en shell 'or th'elilce which may besecured abushing of any desired-size of internal opening and. arranged toresiliently gnipbhenbar of stock.-

As shown in Figs; 1 and 23 the improved pusher includes a;- she'li: t0formed. with: longitudinal slots H: extendingoiinwardiy/ from the:forward 611211 of: the shell and terminatingapertures I32; "liheishelllrflimay hemmed: integrally with a: pushertube notshown; or the innerend l4-- of the shell may be threaded for engagement with the pushertube. The shell I is preferably slotted and the segments so formed arebent inwardly prior to the hardening thereof sothat the shell will exerta spring pressure upon a bushing engaging the stock.

The outer end of the slots II are widened to define keyways H: whichterminate in L-shaped cutouts or guideways 16 for the reception ofsuitable locking keys or studs. The forward end of the shell I0 iscounterbored to define a shoulder l1 disposed intermediate the ends ofthe shell, which engages the rear end of a bushing to aid in the wedgingof the bushing upon a piece of bar stock.

A bushing l8, Fig. 4, is positioned within the forward end of the shelll8 and is provided with an enlarged or thickened forward end portion is,terminating in the flange 20. The end portion l9 of the bushing isformed with an inwardly tapered surface 2| which engages the forward endsurface 22 of the shell Ill. The center portion of the bushing I8 isformed with an external diameter slightly less than the internaldiameter of the counterbored portion of the shell. The rear end of thebushing 18 is provided with an inwardly tapered surface 24 which engagesthe shoulder ll formed in the shell. Upon the positioning of the bushingl8 in the shell ID the rear tapered surface 24 of the bushing is readilyinserted within the counterbored portion of the shell to initiallyexpand the spring segments of the shell whereby the center portion ofthe bushing may then be forced into the shell.

The bushing 18 is divided into three segmental portions 26 bylongitudinal cuts or slots 21. A stud or looking key 28 is threadedinto, or otherwise secured to, each of the segmental portions 26intermediate the ends of the bushing. The studs 28 project from thebushing l8- a distance substantially equal to the thickness of the shellI0 and are arranged to extend through the cutouts or guideways N of theshell upon the insertion of the bushing therein. Each of the portions ofthe cutouts or guideways 16 having the greater axial length is providedwith an abutment surface 29 engageable with the studs 28 for retractingthe bushing l8 upon the rearward movement of the shell ID.

A spring collar or band 30 encircles the enlarged end portion IQ of thebushing for initially urging the segmental portions 26 of the bushinginto engagement with the bar stock S. The spring is held from slippingoff the bushing by the flange 20.

Although the longitudinal slots II in theshell Ill preferably extendinto the cutouts or guideways l6 for the reception of the studs 28, as11- lustrated, it will be understood that it is not necessary for theslots H to intersect the keyways l5 and cutouts I6. The slots ll renderthe shell resilient and the keyways l5 and cutouts I6 cooperate with thestuds 28 on the bushing. Combining them, as illustrated, reduces thenumber of cuts that must be made through the front edge of the shell,but in this form of the invention there is no critical relation betweenthe positions of the slots and keyways.

In the assembly and use of the improved pusher, the rear end of thebushing l8, being of a smaller diameter than the contracted segments ofthe shell I0, is inserted within the shell and the tapered rear surface24 tends to expand the shell segments to facilitate the positioning ofthe bushing in the shell. As the bushing I8 is inserted within the shellthe studs 28 move through the keyways [5 into the portions of thecutouts l6 having the greater axial length, as illustrated in Fig. l.The spring tension of the shell segments, bushing, and spring 30 combineto give the bushing a secure grip upon the stock S.

Upon the initial forward movement of the pusher tube, which carries theshell ID, the tapered surface 2| at the forward end of the bushingcooperates with the surface 22 at the outer end of the shell In so thatthe segments of the shell wedge the forward end of the bushing in-Wardly to securely grip the stock S. Subsequent the initial wedgingaction of the forward end of the bushing l8, by the shell [0, theshoulder H in the shell engages the rear tapered surface 24 of thebushing so that upon the continued forward movement of the shell theshoulder |l urges the rear surface 24 of the bushing into tightengagement with the stock S. During the wedging of the bushing I8 uponthe stock S by the forward movement of the shell 10, the studs 28 aredisposed within the portions of the cutouts l6 having the greater axiallength.

In normal operation the stock S is rotated in a clockwise direction, asviewed from the rear end of the shell H], which movement is transmittedto the bushing l8 and shell l0 through the wedging of the bushing uponthe stock. The studs 28 are adapted to move within the portions of thecutouts l6 having the greater axial length, and engage the shell ID toinsure its rotation with respect to the bushing and stock S.

Upon the rearward movement or return stroke of the pusher tube the shellis retracted, causing the wedging grip of the shoulder I1 and surface 22to be released from the tapered surfaces 2| and 24 of the bushing l8. Asthe shell I0 is retracted the abutting surfaces 29, defined by thecutouts I6, engage the studs 28, thus transmitting the rearward movementof the shell and pusher tube to the bushing. The bushing at this stageof the operation has only a light grip on 7 the stock S, resulting fromthe spring collar 30, and is readily moved over the stock withoutscratching or scoring the same. Thus the pusher normally exerts apositive grip on the stock during the feeding or forward stroke which isreduced to such a degree on the retracting stroke as to avoid scoring ormarring of the bar of stock and excessive wear on the engaging surfacesof the bushing.

When it is desired to withdraw the bar of stock from the pusher, thecollet of the machine is closed upon the stock and a suitable tool, suchas a wrench, is applied to the pusher tube, at the rear end of themachine, for rotating the shell in a clockwise direction. The turning ofthe shell [0 causes the studs 28 to be moved into the portions of thecutout I6 having the shorter axial length. In this position, the studs28 prevent relative axial movement of the shell and bushing and theconsequent engagement of the tapered and beveled surfaces. If the studs28 are not disposed in alignment with the portions of the cutouts I6having the shorter axial length it is only necessary to slide the shelll0 axially a sufficient distance to align the studs 28 with the portionsof the cutout prior to rotating the shell.

In pushers for the smaller sizes of machines, the spring tension exertedby the shell on the bushing'is relatively light, and the stock may beWithdrawn from the pusher by grasping the from end to end.

stock and rotating the same in a counter-clockwi's'e direction.The'bushing I8 is retained in engagement with the stock S through thepressure of the spring collar 30'sothat the turning of the stock istransmitted to the bushing to move the studs 28 into the portion of thecutouts having the shorter axial length.

When the bar is removed from the pusher the bushing I8 collapsesinwardly the distance between the segmental portions 26 formed by theslots 21. As the bushing collapses the segmental portions of the shellI8 formed by the slots II are likewise collapsed, thus retaining thestuds in the cutouts I6 and insuring the retension of the bushing withinthe shell.

;,In the form of the invention shown in Figs. to 11, the shell H8 isprovided with two oppositely disposed slots III extending rearwardlyfrom the forward edge and terminating in holes I. I-2, and two L-shapecl cutouts H6 arranged opposite each other and spacedcircumferentially from the slots III. The slots III are widened adjacentthe front end of. the shell, forming keyways II'5. The shell iscounterbored from its front enda short distance to a wedging surfaceII1. If desired, a smaller counterbore may be continued from the wedgingsurface M1 to a shoulder I3I, arranged to positively limit relativeaxial movement of the shell and bushing.

A one-piece bushing H8 is arranged tofit within the shell II'fi'. Atitsforwardend the bushing has a spring retaining flange I28, and at itsrearward end is tapered to form face II'I' on the shell.

The-bushing is rendered resilient by three slots I25, I26, and I21. Theslot I extends into the bushing from its front end but'stops short ofthe rear end so as not tosever the bushing. Similarly, the slot I26extends into the bushing from its rear end but stops short of the frontend. The slot I21 extends through the bushing Before-hardening, thebushing is given an inward set. tending to collapse the front end of theslot I25, the rear end.- of the slot I26; and the entire length of theslot I21. Thus when finished and hardened the bushin may be forced opento receive the stock and exert a spring grip upon the stock.

The bushing is also provided with a pair of oppositely disposed studs I28 secured in place in any desired manner, as by threaded shanks screwedinto tapped holes in the bushing, as

illustrated. Preferably the studs are square in outline. and after beingscrewed into position: are welded in place with two sides parallel withthe axis of the bushing.

Each of the cutouts IIS has .a rearwardly facing edge I29 adaptedtoengage the forward edge of one of the studs I28 to pull the bushingrearwardly on the retracting stroke of the pusher Each cutout longerax-ially than the studs I28, in which one of the studs may work topermit relative axial movement of the shell and bushing, and a shorterportion, or notch, I 32 adapted to receive a stud I28 and limit relativeaxial movement of the shell and bushing.

The longitudinal edge of each notch I32 is beveled as indicated at I33,and the cooperating longitudinal edge of each stud I28.is formed with acomplemental bevel as indicated at I34. Similarly, one of thelongitudinal edges of eachkeyway III is bevelled as shown at I35 (Figs.L-9) to cooperate with the bevels I34 on the studs.

\ The bushing is arranged to grip the stocka wedging surface I24arranged to cooperate with the wedging sur- III; has a portion which isresiliently by reason of the inward set given the portions separated bythe slots I25, I28, and I21. When desired or needed, additional grippingforce may be obtained by a spring I38 disposed around the front end ofthe bushing and held in place by the flange I20.

To assemble the pusher, the bushing is held with the studs I28 alignedwith the keyways H5 and the rear end of the bushing, which is smaller indiameter than the main body by reason of the tapered surface I24, isinserted into the collapsed front end of the shell 0. The bushing isthen pushed rearwardly, the tapered surface I24 wedging the shell opento receive the bushing, until the studs I28 are positioned in thekeyways II5, the parts then occupying the position shown in Fig. 7. Thebushing is then turned clockwise, as viewed from the front, and thebevelled edges I34 of the studs with the bevelled edges I35 of thekeyways spreads the shell farther open to permit the studs I28 to passunder the walls of the shell. The turning of the bushing is continueduntil the studs snap into the L-shaped cutouts II B, as shown in Fig. 8.

In operation the studs normally lie in the portions of the cutouts II6having the greater axial length by reason of the rotation of the stock,as in the embodiment previously described. On the forward stroke of thepusher tube the wedging surface II! on the shell moves over the taperedsurface I24 of the bushing to increase the grip of the bushing on thestock. On the rearward stroke, the edges I29 of the cutouts engage thestuds and slide the bushing over the stock against the relatively lightgrip provided by the resilience of the bushing. When it is desired towithdraw the bar of stock the studs are turned into the notches I32 toprevent weclging engagement of the surfaces I I1 and I24, as in theembodiment previously described.

When it is desired to remove the bushing from the shell. the bushing isturned so that the studs I28 enter the notches I32 and the bevellededges I34 on the studs engage the bevelled edges I 33 of the notches.The bushing is then turned forcibly in a clockwise direction to spreadthe shell open and permit the studs to pass under the walls of theshell. The bushing is then pulled forwardly and out of the shell.

A further modification of the invention is shown in Figs. 12 to 14inclusive. In this form the shell 2H1 is rendered resilient by threeslots 2II terminating in holes 2I2. The shell is formed with threekeyways 2I5 leading in from its front edge and opening into cutouts 2I6.The shell is provided with a 'counterbore terminating in a wedgingsurface 2I1.

The bushing 2I8 is formed of three segments 226 separated by slots 221.The forward end of the bushing is provided with a flange 225 whichserves to retain a spring 238. The rear end of the bushing is formedwith a tapered surface 224 to cooperate with the wedging surface 2H onthe shell. Each of the segments 226 is provided with a stud 228,corresponding to the studs 28 and I28 in the modifications previouslydescribed, which fits within one of the cutouts M6 in the shell. Theassembly, disassembly, and

operation of this form of the invention are the I 28 cooperating inginto the collapsed slots 31!, the shell being given an inward set beforehardening, as in the other forms, so that the shell presses upon thebushing.

The shell (H l is formed on its inner surface with threads 340, whichare preferably square in cross section. Beyond the threads the innersurface of the shell is tapered to provide a wedging surface 3.

The bushing BIB consists of three segments 326 separated by slots 32'!and held together by a spring 330 engaging a flange 320. At its rear endthe bushing is formed with a tapered surface 324 for cooperation withthe wedging surface (Hi. In front of the surface 324 the bushing isprovided with exterior threads 34f complemental to the threads 340 inthe shell.

The bushing M8 is assembled into the shell 3H3 by inserting the taperedrear end of the bushshell and spreading the shell until the threads 340and 34! engage. The bushing is then turned until the threads 34! on thebushing pass completely through the threads 346 on the shell. Thebushing is then positioned as shown in Fig. with the tapered surface 324ready to engage the wedging surface 3i? on the advancing stroke of thepusher and with the rear side of the threads 348 ready to engage thefront side of the threads 34l to pull the bushing rearwardly on theretracting stroke.

To remove the bushing 3i8, it is only necessary to turn the bushing inthe direction opposite to its normal direction of rotation so as tostart the threads 3M into the threads 3411, after which the bushing maybe screwed out of the shell. In the illustrated embodiment the threads340 and 3M are left hand to suit a machine in which the pusher tube isnot driven except as it is rotated by the stock, and in which the stockis rotated in a counterclockwise direction as viewed from the front endof the spindle.

In the illustrated embodiment, the threads 34d and 34! are cut with adouble lead, so that the threads always have at least two bearings oneach other at diametrically opposite points when the shell pulls thebushing on its retracting stroke. Fig. 19 is a developed view of theentire surface of the threaded end of the shell, showing the two ends342 and 343 of the double lead thread disposed 180 degrees apart. Itwill be understood that the threads may have as many eads as desired.

In operation the wedging surface 3l1 on the shell engages the taperedsurface 324 on the bushing when the shell moves forwardly to increasethe grip of the bushing on the stock as in the embodiments previouslydescribed. When it is desired to withdraw the bar of stock being workedupon it is only necessary to turn the brushing in the direction oppositeto its normal direction of rotation so as to start the threads 34l intothe threads 340 after which the bar may be withdrawn. rearwardly fromthe machine without causing engagement of the wedging surface 3H and thetapered surface 324. When a new bar is placed in position the normalrotation of the machine immediately turns the threads 340 and 341 out ofengagement and into the normal operative position, as illustrated inFig. 15.

In Figs. 17 and 18 the surfaces 3H and 324 are shown as knurled orroughened in order to minimize relative rotation between the bushing andthe shell. In machines in which the pusher tube is not driven by thespindle the stock normally drives the shell and pusher tube throughbetween the parts.

the friction of the shell on the bushing when the stock is gripped bythe collet and being rotated. Roughening the surfaces 3!! and 324reduces the relative slippage and consequent wear Manifestly thisfeature may be applied when desired to any of the various forms of theinvention.

Although preferred embodiments of the invention have been described inconsiderable detail it will be understood that various modifications andre-arrangements of the parts may be resorted to without departing fromthe scope of the invention as defined in the following claims.

I claim:

1. In a pusher, a collapsible bushing arranged to resiliently grip stockto be fed, a tubular shell having slots extending inwardly from itsfront edge, the slotted portions of said shell being bent inwardly to adiameter smaller than the outside diameter of said bushing when saidbushing is collapsed, said shell surrounding and resiliently grippingsaid bushing when said bushing is collapsed, said bushing being taperedat its rear end to a size sufficiently small to enter the front end ofsaid shell when the same is collapsed, whereby said bushing may beforced rearwardly into said shell to spread the same, and cooperatingabutments on said bushing and shell engageable in normal operativeposition to hold said bushing against forward movement with respect tosaid shell.

2. In a pusher, a collapsible bushing arranged to resiliently grip stockto be fed, a tubular shell having slots extending inwardly from itsfront edge, the slotted portions of said shell being bent inwardly to adiameter smaller than the outside diameter of said bushing when saidbushing is collapsed, said shell surrounding and resiliently grippingsaid bushing when said bushing is collapsed, said bushing being taperedat its rear end to a size sufficiently small to enter the front end ofsaid shell when the same is collapsed, whereby said bushing may beforced rearwardly into said shell to spread the same, a radiallyprojecting lug on said bushing and said shell being formed with anopening through the wall thereof to receive said lug in normal operativeposition to hold said bushing against forward movement with respect tosaid shell, said shell being arranged to collapse upon said bushing whenno stock is gripped by said bushing so as to maintain said lug in saidopening at all times.

3. In a pusher, a collapsible bushing arranged to resiliently grip stockto be fed, a tubular shell having slots extending inwardly from itsfront edge, said shell surrounding and resiliently gripping said bushingwhen said bushing is collapsed, said bushing being tapered at its rearend to a size sufficiently small to enter the front end of said shellwhen the same is collapsed, whereby said bushing may be forcedrearwardly into said shell to spread the same, said bushing having aradially projecting member, said shell being formed with an abutmentengaging said member in normal operative position to hold said bushingagainst forward movement with respect to said shell, and a surface onsaid shell arranged to engage said tapered rear end of said bushing toincrease the grip of said bushing on the stock when said bushing movesrearwardly with respect to said shell.

4. In a pusher, a collapsible bushing arranged to resiliently grip stockto be fed, a tubular shell having slots extending inwardly from itsfront gedge, said shell surrounding and resiliently {gripping saidbushing when said bushing is collapsed, 'said bushing being tapered atits rear end to a sizesufficiently small to enter :the front end .of

vsaid Shell when the same is collapsed, whereby said bushing may beforcedrearwardly into said ;operativeposition to hold said bushingagainst forward movement with respect to said shell, and

a surface on said shell arrangedto engage the :tapered rear end of saidbushing to increase the grip of said bushing on the stock when saidbushingmoves rearwardly with respect to said shell.

5. In :a pusher, a collapsible bushing arranged to resiliently gripstock :to be fed, a tubular shell having slots extending inwardly fromits front edge, said shell surrounding and resiliently gripping saidbushing, said bushing being tapered at its rear end to a sizesufficiently small to enter .the front end of said shell when the sameis collapsed, whereby-said bushing may be forced rearwardly into saidshell to spread the same, said bushing carrying a radially projectingmember, said shell being formed with an abutment engaging said member innormal operative position to hold said bushing against forward movementwith respect to :said shell, a surface on said shell arranged to engagethe tapered rear end of said bushing to increase the grip thereof on thestock when said bushing moves rearwardly with respect to said shell, andabutment surfaces on said shell and bushing adapted to be brought intoalignment by relative rotation between said shell and bushing to preventengagement of said surface with the tapered rear end of said bushing.

-6. In a pusher, a collapsible bushing arranged to resiliently gripstock to be fed, a tubular shell vvhaving slots extending inwardly fromits front edge rendering the same resilient, said shell beingtensionedinwardly to resiliently grip said bushing, a radiallyprojecting abutment carried by said bushing, said shell being formedwith a keyway extending inwardly from its front edge and a communicatingcutout spaced from said front edge and offset from said keyway, saidkeyway being of sufiicient width to receive said abutment, whereby saidbushing may be'forced rearwardly into said shell with said abutmentpassing through said keyway, and said cutout having a rearwardly facingedge adapted to engage said abutment in normal operative position tohold said bushing against forward movement with re- :spect to said shelland an edge facing laterally toward said keyway to engage said abutmentand resist relative rotation of said bushing and said shell in onedirection.

7. In a pusher, a collapsible bushing arranged to resiliently grip stockto be fed, a tubular shell having slots extending inwardly from itsfront edge rendering the same resilient, said shell being tensionedinwardly to resiliently grip said bushing, said bushing being tapered atits rear end to a size sufiiciently small to enter the front end of saidshell when thesame is collapsed, a radially'projecting abutment carriedby said bushin said shell being formed with a keyway extending inwardlyfrom its front edge and a communicating cutout spaced from said frontedge and offset from said keyway, said keyway being of sufficient widthto receive said abutment, whereby said bushing maybe forced rearwardlyinto said shell with said abutment passing through said keyway,

shell to spread the same, cooperating abutments ,on said bushing andshell engageable in normal and said cutout having a rearwardly facingedge adapted to engage said abutment in normal operative position tohold said bushing against forward movement with respect to saidshell-and an edge facing laterally toward said keyway to engage saidabutment and resist relative rotation of said bushing and said shell inonedirection;

8. In a pusher, a collapsible bushing arranged to resilientlygrip stockto be fed, a tubular shell having slots extending inwardly from itsfront edge rendering the same resilient, said shell being tensionedinwardly to resiliently grip'said bushing, a radially projectingabutment carried by said bushing, said shell being formed with a keywayextending inwardly from its front edge and a communicating cutout spacedfrom said front edge and offset from said keyway, said keyway being ofsufficient width to receive saidabutment,

whereby said bushing may be forced rearwardly into said shell with saidabutment passing through said keyway, and said cutout having arearwardly facing edge adapted to engage said abutment in normaloperative position to hold said bushing against forward movement withrespect to said shell .and an edge facing laterally toward said keywayto engage said abutment and resist relative rotation of said bushing andsaid shell in one direction, and cooperating wedging surfaces on saidshell and said bushing to increase the grip of said bushing on the stockwhen said bushing moves rearwardly with respect to said shell. I

9. Inapusher, a collapsible bushing arranged to resiliently .grip stockto be fed, .a tubular shell having slots extending inwardly from itsfront edge rendering the same resilient, saidshell being tensionedinwardly to resiliently grip said bushing, the rear end of .said bushingbeing tapered to a size sufficiently small ,to-enter ,the front end ofsaid shell when the same is collapsed, radially projecting abutmentscarried by said bushing, said shell being formed with ,keywaysextendinginwardly from its front edge and with a cutout communicating with each[of said keyways spaced from the front edgeand offset fromsaid keywaysin the direction of normal rotation of'the stock,

said keyways being .of sufficient width to receive said abutments,whereby said bushin may be forced rearwardly into said shell with-saidabutments passin through said key-ways and may be turned in thedirection of normal rotation to bring said abutments into said cutouts,and said cutouts having rearwardly facing edges adapted to engage saidabutments .in normal operative position to-hold said bushing againstforward movement with respect to said shell and edges facing laterallytoward said keyways adapted to engage said abutments and resist relativerotation of said bushing and said shell in one direction.

10. In apusher, a collapsible bushing arranged to resiliently grip stockto be fed, a tubular shell having slots extending inwardly from itsfront edgerendering the same resilient, said shell being tensionedinwardly to-resiliently gripsaid bushing, a radially projecting studcarried :by said bushing having one side edge bevelled, said shell beingformed with a keyway extending into the same from its front edge and arecess spaced from the fronttedge and from said keyway, whereby saidbus-hing ,may be pushed into said shell with said stud passing throughsaid keyway and may .be turned to force the beveled edge of said studagainst :an edge of said "keyway to expand said shell and permit saidstud to be positioned in said recess.

11. In a pusher, a collapsible bushing arranged to resiliently gripstock to be fed, a tubular shell having slots extending inwardly fromits front edge rendering the same resilient, said shell being tensionedinwardly to resiliently grip said bushing, said bushing being tapered atits rearend to a size sufficiently small to enter the front end of saidshell when the same is collapsed, a radially projecting stud carried bysaid bushing having one side edge bevelled, said shell being formed witha keyway extending into the same from its front edge and a recess spacedfrom the front edge and from said keyway, whereby said bushing may bepushed into said shell to expand the same with said stud passing throughsaid keyway and may be turned to force the bevelled edge of said studagainst an edge of said keyway to further expand said shell and permitsaid stud to be positioned in said recess.

12. In a pusher, a collapsible bushing arranged to resiliently gripstock to be fed, a tubular shell having slots extending inwardly fromits front edge rendering the same resilient, said shell being tensionedinwardly to resiliently grip said bushing, a radially projecting studcarried by said bushing having one side edge bevelled, said shell beingformed with a. keyway extending into the same from its front edge and arecess spaced from the front edge and from said keyway, whereby saidbushing may be pushed into said shell with said stud passing throughsaid keyway and may be turned to force the beveled edge of said studagainst an edge of said keyway to expand said shell and permit said studto be positioned in said recess in normal operative position, saidrecess having one side edge arranged to cooperate with the bevelled sideof said stud whereby rotation of said bushing from its normal operativeposition expands said shell and forces said stud under said shell topermit removal of said bushing.

13. In a pusher, a collapsible bushing arranged to resiliently gripstock to be fed, a tubular shell having slots extending inwardly fromits front edge rendering the same resilient, said shell being tensionedinwardly to resiliently grip said bushing, the rear end of said bushingbeing tapered to a size sufiiciently small to enter the front end ofsaid shell when the same is collapsed, a radially projecting studcarried by said bushing having one side edge bevelled, said shell beingformed with a keyway extending into thesame from its front edge and arecess spaced from the front edge and from said keyway, whereby saidbushing may be pushed into said shell with said stud passing throughsaid keyway and mat be turned to force the bevelled edge of said studagainst an edge of said keyway to expand said shell and permit said studto be positioned in said recess in normal operative position, saidrecess having an edge arranged to engage said stud to prevent forwardmovement of said bushing with respect to said shell, and said shellhaving a wedging surface arranged to engage the tapered rear end of saidbushing to increase the grip thereof on the stock when said bushingmoves rearwardly with respect to said shell.

14. In a pusher, a collapsible bushing arranged to resiliently gripstock to be fed, a tubular shell surrounding said bushing and havingslots extending inwardly from its front edge rendering the sameresilient, said shell being tensioned inwardly to resiliently grip saidbushing when said bushing is collapsed, the inner surface of said shellbeing formed with screw threads, and cooperating screw threads on theouter surface of a portion of said bushing positioned rearwardly of thethreads on said shell in the normal operative position of the bushing,said threads being engageable to permit installation or removal of saidbushing through the front end of said shell by screwing the threads onthe bushing through the threads on the shell.

15. In a pusher, a collapsible bushing arranged to resiliently gripstock to be fed, a tubular shell surrounding said bushing and havingslots extending inwardly from its front edge rendering the sameresilient, said shell being tensioned inwardly to resiliently grip saidbushing, the rear end of said bushing being tapered to a sizesufficiently small to enterthe front end of said shell when the same iscollapsed, the inner surface of said shell being formed with screwthreads, and cooperating screw threads formed on said bushing in frontof the tapered rear end thereof and positioned rearwardly of the threadson said shell in the normal operative position of said bushing.

16. In a pusher, a collapsible bushing arranged to resiliently grip.stock to befed, a tubular shell surrounding said bushing and havingslots extending inwardly from its front edge rendering the sameresilient, said shell being tensioned inwardly to resiliently grip saidbushing, the inner surface of said shell being formed with screwthreads, and cooperating screw threads on said bushing positionedrearwardly of the threads on said shell in the normal operative positionof said bushing, the front ends of the threads on said bushing beingadapted to engage the rear ends of the threads on. said shell to preventforward movement of said bushing with respect to said shell, andcooperating wedging surfaces arranged to engage to increase the grip ofthe bushing on the stock when said bushing moves rearwardly with respectto said shell.

17. In a pusher, a collapsible bushing arranged to resiliently gripstock to be fed, a tubular shell surrounding said bushing and havingslots extending inwardly from its front edge rendering the sameresilient, said shell being tensioned inwardly to resiliently grip saidbushing, the rear end of said bushing being tapered to a sizesufficiently small to enter the front end of said shell when the same iscollapsed, the inner surface of said shell being formed with screwthreads, cooperating screw threads on said bushing positioned rearwardlyof the threads on said shell in the normal operative position of saidbushing and adapted to engage the rear ends of the threads in said shellto prevent forward movement of said bushing with respect to said shell,and a wedging surface on said shell arranged to engagethe tapered rearend of said bushing to increase the grip thereof on the stock when saidbushing moves rearwardly with respect to said shell.

18. In a pusher, a collapsible bushing arranged to resiliently gripstock to be fed, a tubular shell having slots extending inwardly fromits front edge, said shell surrounding 'and resiliently gripping saidbushing when said bushing is collapsed, said bushing being tapered atits rear end to a size sufficiently small to enter the front end of saidshell when the same is collapsed, whereby said bushing may be forcedrearwardly into said shell to spread the same, said bushing having aradially projecting member, said shell ,being formed with an openingreceiving said member in normal operative position to hold said bushingagainst forward movement with respect to said shell, a surface on saidshell arranged to engage said tapered rear end of said bushing toincrease the grip of said bushing on the stock 5' when said bushingmoves rearwardly with respect to said shell, and said bushing beingformed with a portion projecting from the front end of the shell havinga surface tapering to a diameter larger than the inside diameter of theshell arranged to engage the front end of the shell to increase the gripof the bushing on the stock when said bushing moves rearwardly withrespect to said shell.

STODDARD B. Ml iR'IIN.

